Our objective is to study the natural history, self-management, and impact of physical and mental health comorbidities on the outcomes of World Trade Center (WTC) rescue and recovery workers with asthma. Asthma is a common illness among WTC workers (9-year cumulative incidence is approximately 28%) and is responsible for a high rate of morbidity and diminished quality of life in this population. This level of morbidity may be attributable in part to WTC-related exposures, the added complexity imparted by multiple coexisting physical and mental conditions, and the health beliefs that often shape self-management behaviors of asthmatics. While several studies have described the incidence of asthma, there is limited data regarding the natural history, self- management, and impact of comorbidities on the outcomes of WTC workers with asthma. Accordingly, the Specific Aims of the proposal are: 1) assess the clinical (allergic sensitization, severity, medication needs), physiologic (lung function impairment), etiologic characteristics (irritant induced vs. non-irritan induced, risk factors for severe persistent asthma), and natural history of asthma in WTC workers; 2) evaluate the relationship and impact of upper airway conditions (rhinitis, sinusitis), gatroesophageal reflux disease (GERD), and obstructive sleep apnea (OSA) on asthma morbidity (control and quality of life) in WTC rescue and recovery workers; 3) assess the impact of comorbid mental health conditions (depression and post-traumatic stress disorder [PTSD]) on asthma self-management behaviors (medication adherence, self-monitoring, use of action plans, and allergy avoidance) and outcomes (asthma control, resource utilization, and quality of life); and 4) evaluate the influence of disease and medication beliefs on self-management behaviors in WTC workers with asthma. We will conduct a prospective cohort study of 400 WTC rescue and recovery workers with a physician diagnosis of asthma that are enrolled at the Mount Sinai Hospital or North Shore-Long Island Jewish/Queen College sites of the WTC Health Program. Study subjects will undergo comprehensive baseline evaluation to collect data on asthma history, medication requirements, asthma control and quality of life, WTC- exposures, physical and mental health comorbidities, disease and medication beliefs, and self-management behaviors. We will use psychiatric interviews to assess major depression and post traumatic stress disorders (PTSD) in WTC workers with asthma. Participants will be followed at 6 and 12 months to assess the interplay of physical and mental health comorbidities with asthma and prospectively evaluate the pathways explaining self-management behaviors. We aim to identify specific, modifiable factors that mediate asthma self-management and morbidity, offering us an opportunity to develop interventions to improve asthma outcomes in WTC workers with this condition.